2000 with automatic air controls. The control module shows no visible signs of degradation (no burnt tracks or components). I tested the fan by grounding the fan case directly to the battery. It ran at full speed. GP202 and the pins within the connector show no signs of corrosion. My best guess is the control module. Is there anything else it could be before I drop $150 on a new control module?
Thanks in advance!

 

The transistors inside the module that control speed seem to short and draw too much current. That causes the printed circuit board inside to fry!










Its easy to disassemble. Hey,, what do you have to loose?

BC

 

52479971, search this number on Ebay and get a used one, I got a good one for $35 shipped.

You could also try a junkyard and check out similar years of some Pontiac Grand Prix as well as a some Buick Regals used the same one the C5 used.

You can get a half dozen used ones for the price of a new one, and they are most likely GM original.

 

Bill, I did pop the controller module open and take a look. It looks fine. I didn't see any signs of overstress or damage to components or traces (at least external). If the transistors were to short out I would expect it to either burn up the traces like you show in your pictures or blow the 30A fuse. Neither of these have happened. It just stops blowing right after the fan is turned up to high. Once the fan speed is lowered it will kick on and work properly. That is what lead me to believe the ground is bad (or at least not ideal). But the ground pack looks fine also. I'd post pics of all of these parts if I could figure out how (please enter URL of your image..?).

I believe my '00 electrical circuit matches the '01 you originally posted in this thread. Any harm in adding an additional ground wire coming directly from the ground pin of the control module (pin A per the schematic or T1 as labeled on the control module PWA) to a chassis ground point? Maybe then it will have sufficient ground to burn up the track and then the controller WILL be visibly damaged That would almost be comical! At least the AC works at lower fan speeds so I can still joke about it.

Then I can go to ebay and get the part number vetteman741 provided (this matches the one on my control module).

 

So which one is pin "F" the top right or bottom left, I guess I will check both of them.

 

Blew the 30 amp fuse POOF. I got a new one at GM wholesaler for abt $90. If you can find a used one for half the price go for it.

 

I figure it's probably not a good idea to try to blow the controller completely if it truly is on its last leg. Then I would be without AC completely until the new controller arrived. So I hit up Ebay and got one for $37. It will hopefully be here in a week. I'll report back once I get it installed. If that doesn't fix it I think I'll have to try the additional ground wire.

 

So, I got the replacement control module installed on Sunday. Sure enough, it solved the problem! Rock on! I'm finally back to full blast AC which I will certainly need tomorrow afternoon. Thanks to all for the help! Great pictures Bill. They made it easy to locate the offending component. Thanks vetteman741 for the ebay suggestion. I hadn't even thought of that.

 

I'm happy to hear it's worked out for you. I'm having the same issue. I'll give this a try.

 

I had just solved my issues (or so I thought) when I replaced my module. The blower was OK, but showed signs of corrosion, Since it was a P.I.T.A. to get at (I'm a big guy with stiff joints) I figured I might as well replace that too, as I was already in there.

Worked great for 2 months or so, then 4 days ago, no blower again.

Go out today, hit the A/C, it works like a champ. Guess I'll be checking grounds this weekend.